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- Dictionaryfre·quen·cy/ˈfrēkwənsē/
noun
- 1. the rate at which something occurs or is repeated over a particular period of time or in a given sample: "an increase in the frequency of accidents due to increased overtime"
- 2. the rate at which a vibration occurs that constitutes a wave, either in a material (as in sound waves), or in an electromagnetic field (as in radio waves and light), usually measured per second: "different thicknesses of glass will absorb different frequencies of sound"
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Frequency of a signal means the number of occurrences of a repeating event per unit of time. So if the unit of time is seconds then frequency is measured with Herz: 1Hz = 1/s. So a signal with 100Hz, has a pattern that repeats 100 times per second. The most basic signal (from the point of view of signal processing) is a sinus signal. y(t) = sin ...
5. Moiré is an interference pattern. In photography many times it is noticed on the fine detail of a woman's clothing, or a repetitive pattern in architecture. Moiré can be caused by a scene that contains areas with repetitive detail which exceed the resolution of the camera. Anti-alias filters reduce or eliminate moiré but also reduce image ...
Actually, you can do amazing stuff to images with fourier transform operations, including: (1) re-focus out of focus images (2) remove pattern noise in a picture, such as a half-tone mask (3) remove a repeating pattern like taking a picture through a screen door or off a piece of embossed paper (4) find an image so deeply buried in noise you ...
Sep 28, 2016 · The golden hour is the period of time (roughly an hour) immediately either side of sunrise/sunset. At this time the sun is very low in the sky. As a result the light passes through much more of the atmosphere. The result of this is that: the high frequencies (blues) are filtered out giving a very warm light. the light is diffused by particles ...
Nyquist frequency - The highest frequency continuous signal that can be represented by a discreet signal (for a given sampling frequency). These two terms are two sides of the same coin. The first gives you a bound on sampling rate as a function of max frequency. The second gives you the max possible frequency as a function of sampling rate.
Feb 6, 2011 · The diffraction cutoff frequency is generally the point where resolution reaches the wavelength of the frequencies of light itself. For visible light, λ between 380–750nm, or 0.38–0.75 microns. Until the cutoff frequency has been met for a given aperture, more resolution can be achieved. Visual Examples
You can use frequency modulation for printing color images as well. Dithering has a specific technical definition used more in digital images instead of the printing world. According to Wikipedia -- "Dithering is a technique used in computer graphics to create the illusion of color depth in images with a limited color palette (color quantization).
Softness - in its most basic sense, is a lack of (or less) edge definition (edge contrast) and/or fine detail, when compared with a "sharp" image. It is not possible for a single coloured image (eg an image containing only a red fill) , or an image with very little detail, such as a gentle fade, to be classed as either soft or sharp, as there is no defined contract area or fine detail to base ...
The relative mix of blue and yellow and the exact emitted frequency ranges are varies to produc elight ranging from "warm white" (around 2500 - 3500 Kelvin effective colour temperature) up through daylight like whites in the 4000K - 7000k range and then to distnctly blue whites up to about 10,000 K equivalent.
Apr 18, 2012 · Brightness constancy with directed edges (bilinear direction). Artifacts: high frequency texture moire, colour fringing; Hue constancy. if in a neighborhood the hue is the same, so if one channel changes the others have to follow. Artifacts: colour zippers on colour edges; Constancy can be predicted from the greens. Artifact: mazes
